Hinokitiol (chemical name: 4-isopropyl-2-hydroxy-cyclohepta-2,4,6-triene-1-on) is extracted from natural products such as hinoki oil and hiba oil, or is chemically synthesized. Hinokitiol is known for its excellent antibacterial, bactericidal, and antiseptic effects and also for being mild to the skin of the human body or the like. As already proposed, hinokitiol or its metal salt can be used as an aqueous solution for killing and disinfecting various bacteria (see, for example, Japanese Patent Application Laid-open Nos. 2000-342236, 2001-131061, and 2002-238524).
Being water-based agents, these bactericidal disinfecting agents may be left unremoved after application. Even when they are applied to the human body, no washing operation is necessary. Nevertheless, these agents present some other problems. For example, the aqueous solution dribbles when it is dispensed from a container and applied by a hand or when it is sprayed directly from a container. Besides, unlike the alcohol-based agent which dries fast, the water-based agent leaves the application area dripping wet. Particularly when the aqueous solution is applied to the human body, the hand and the application area need to be dried, or wiped by a towel or the like. It is therefore desired to provide an easy-to-use bactericidal disinfecting agent which does not encounter such problems.
An example of possible solutions is to make a foam agent. The foam agent does not dribble when dispensed from a container to a hand. Further, compared with the aqueous solution, the foam agent works in a smaller amount of use. As a result, the foam agent does not leave the hand or the application area dripping wet, and does not require a wipe-off, drying or other operation.
Concerning a skin cleansing agent, a foam agent is already disclosed in Japanese Patent Application Laid-open No. 2002-363062. However, this skin cleansing foam agent is not formulated with a bactericidal agent. Generally, it is a surfactant that causes formation of foam. However, this skin cleansing foam agent, which contains a sugar ester-type surfactant such as fatty acid ester of sucrose, turns into foam only insufficiently.